In the absence of the parameter \(c_1\)  (which represents a massive spin-2 hair
[1]}, [2]}),
the metric (REF ) looks very similar to that of the standard Schwarzschild-(A)dS
black hole, provided \(d\)  takes a negative value. Let us stress that,
unlike in most of the other gravity models, the cosmological constant \(\Lambda \) 
arises purely as an integration constant, therefore, this model was once considered to be
very appropriate for pursuing thermodynamic analysis following the extended phase space
approach, because a variable cosmological constant in this
model does not cause the ensemble of theories problem which appears in other
theories of gravity.
